1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method for subjecting a substrate to processing.
2. Description of the Background Art
Substrate processing apparatuses are used to subject various substrates such as semiconductor substrates, substrates for liquid crystal displays, plasma displays, optical disks, magnetic disks, magneto-optical disks, photomasks, and other substrates to various types of processing.
In such substrate processing apparatuses, a substrate before exposure processing is subjected to various types of film formation processing. However, a back surface of the substrate may be contaminated in the process of film formation processing. In this case, irregularities are formed on the back surface of the substrate due to contaminants, resulting in an unstable state of the substrate. This may cause a dimensional error and a shape defect of an exposure pattern during the exposure processing.
In order to avoid such problems, a substrate processing apparatus of JP 2007-214365 A is provided with a back surface cleaning unit that cleans the back surface of the substrate before exposure processing, for example. This allows contaminants adhering to the back surface of the substrate before exposure processing to be removed.
With recent improvements in the density and integration of devices, making finer resist patterns has been required. Resolution performance, which is a key to obtain finer resist patterns, of an exposure device depends on the wavelength of a light source of the exposure device. Exposure techniques that use EUV (extra-ultraviolet) having an extremely short wavelength of about 13 nm have been proposed. Since the EUV is easily absorbed by the air, exposure processing using the EUV needs to be performed in a state whose degree of vacuum is high. Therefore, the substrate in a clean state needs to be carried in the exposure device for performing the exposure processing using the EUV.